If you really are worried about jail time contact a lawyer and most probably delete any trace of the files. If you aren't going to do that, or even if you are,

If you really are worried about jail time contact a lawyer and most probably delete any trace of the files. If you aren't going to do that, or even if you are, contact the people who are storing this in plaintext and tell them why it is wrong perhaps even give an ultimatum for further action. But you probably should talk to a lawyer first make sure you know what you should do.